Application of mucilage from Dicerocaryum eriocarpum plant as biosorption medium in the removal of selected heavy metal ions

A Concise Review on Taro Mucilage: Extraction Techniques, Chemical Composition, Characterization, Applications, and Health Attributes

Taro (Colocasia esculenta) is an important source of carbohydrates as an energy source and is used as a staple food throughout the world. It is rich in mucilage and starch granules, making it a highly digestible ingredient. Mucilage can act as a matrix and a thickening, binding, emulsifying, or foaming agent in food, pharmaceutical, and several other fields of research. Moreover, mucilage can be extracted from several living organisms and has excellent functional properties, such as water-holding, oil-holding, and swelling capacities. Therefore, these remarkable functional properties make mucilage a promising ingredient with possible industrial applications. Furthermore, several extraction techniques, including enzyme-assisted, ultrasonication, microwave-assisted, aquatic, and solvent extraction methods, are used to obtain quantitative amounts of taro mucilage. Coldwater extraction with ethanol precipitation can be considered an effective and cost-effective technique to obtain high-quality mucilage with suitable industrial applications, whereas the ultrasonication method is more expensive but results in a higher amount of mucilage than other emerging techniques. Mucilage can also be used as a fat replacer or reducer, dye remover, coating agent, and antioxidating agent. Therefore, in this review, we detail the key properties related to the extraction techniques, chemical composition, and characterization of taro mucilage, along with its suitable applications and health benefits.

The Renaissance of Plant Mucilage in Health Promotion and Industrial Applications: A Review

Plant mucilage is a renewable and cost-effective source of plant-based compounds that are biologically active, biodegradable, biocompatible, nontoxic, and environmentally friendly. Until recently, plant mucilage has been of interest mostly for technological purposes. This review examined both its traditional uses and potential modern applications in a new generation of health-promoting foods, as well as in cosmetics and biomaterials. We explored the nutritional, phytochemical, and pharmacological richness of plant mucilage, with a particular focus on its biological activity. We also highlighted areas where more research is needed in order to understand the full commercial potential of plant mucilage.

A Comprehensive Review on Plant-Derived Mucilage: Characterization, Functional Properties, Applications, and Its Utilization for Nanocarrier Fabrication

Easily sourced mucus from various plant parts is an odorless, colorless and tasteless substance with emerging commercial potential in agriculture, food, cosmetics and pharmaceuticals due to its non-toxic and biodegradable properties. It has been found that plant-derived mucilage can be used as a natural thickener or emulsifier and an alternative to synthetic polymers and additives. Because it is an invisible barrier that separates the surface from the surrounding atmosphere, it is used as edible coatings to extend the shelf life of fresh vegetables and fruits as well as many food products. In addition to its functional properties, mucilage can also be used for the production of nanocarriers. In this review, we focus on mucus extraction methods and its use as a natural preservative for fresh produce. We detailed the key properties related to the extraction and preservation of food, the mechanism of the effect of mucus on the sensory properties of products, coating methods when using mucus and its recipe for preserving fruit and vegetables. Understanding the ecological, economic and scientific factors of production and the efficiency of mucus as a multi-directional agent will open up its practical application in many industries.

Impact of Land Management on Water Resources, a South African Context

Globally, the changes exerted on the land cover have shown greater impacts on the quality and quantity of water resources and thus affecting catchment’s hydrological response (i.e., runoff, evapotranspiration, infiltration, amongst others). South Africa is a water-scarce country faced with domestic water supply challenges. A systematic review was conducted on the overview impacts of land use/land cover changes on water resources. Despite the country’s best efforts in ensuring the protection and sustainable use of water resources, the review indicated that water quality has been compromised in most parts of the country thus affecting water availability. The increase in water demand with development presents the need for better integrated strategic approaches and a change in behaviour towards water resource and land management. Thus, the review suggested a few possible solutions that will promote sustainable development, while protecting and preserving the integrity of South African water resources.

Arabinoxylan and rhamnogalacturonan mucilage: Outgoing and potential trends of pharmaceutical, environmental, and medicinal merits

Demand for safe, environmentally friendly and minimally processed food additives with intrinsic technological (stabilizing, texturizing, structuring) and functional potential is already on the rise. There are actually several natural excipients eligible for pharmaceutical formulation. Mucilage, as a class constitutes arabinoxylan and rhamnogalacturonan-based biomolecules used in the pharmaceutical, environmental as well as phytoremediation industries owing to its particular structure and properties. These compounds are widely used in pharmaceutical, food and cosmetics, as well as, in agriculture, paper industries. This review emphasizes mucilage valuable applications in the pharmaceutical and industrial fields. In this context, much focus has recently been given to the valorization of mucilage as an ingredient for food or nutraceutical applications. Furthermore, different optimization and extraction techniques are presented to develop better utilization and/or enhanced yield of mucilage. The highlighted mucilage extraction methods warrant assessing up-scale processes to encourage for its industrial applications. The current article capitalizes on cutting-edge characteristics of mucilage and posing for other possible innovative applications in non-food industries. Here, the first holistic overview of mucilage with regards to its physicochemical properties and potential novel usages is presented.

Production and characterisation of activated carbon and carbon nanotubes from potato peel waste and their application in heavy metal removal

Herein, activated carbon (AC) and carbon nanotubes (CNTs) were synthesised from potato peel waste (PPW). Different ACs were synthesised via two activation steps: firstly, with phosphoric acid (designated PP) and then using potassium hydroxide (designated PK). The AC produced after the two activation steps showed a surface area as high as 833 m2 g-1 with a pore volume of 0.44 cm3 g-1, where the raw material of PPW showed a surface area < 4 m2 g-1. This can help aid and facilitate the concept of the circular economy by effectively up-cycling and valorising waste lignocellulosic biomass such as potato peel waste to high surface area AC and subsequently, multi-walled carbon nanotubes (MWCNTs). Consequently, MWCNTs were prepared from the produced AC by mixing it with the nitrogen-based material melamine and iron precursor, iron (III) oxalate hexahydrate. This produced hydrophilic multi-wall carbon nanotubes (MWCNTs) with a water contact angle of θ = 14.97 °. Both AC and CNT materials were used in heavy metal removal (HMR) where the maximum lead absorption was observed for sample PK with a 84% removal capacity after the first hour of testing. This result signifies that the synthesis of these up-cycled materials can have applications in areas such as wastewater treatment or other conventional AC/CNT end uses with a rapid cycle time in a two-fold approach to improve the eco-friendly synthesis of such value-added products and the circular economy from a significant waste stream, i.e., PPW. Graphical abstract .

Gold Biomineralization on Bacterial Biofilms for Leaching of Au3+ Damages Eukaryotic Cells

Heavy metals not only pollute the environment but also are health and environmental hazard. Bacteria constitute inexpensive and eco-friendly material to eliminate and recycle heavy metals via biomineralization and biosorption. However, the effect of metal biomineralization in bacterial biofilms on the ecological balance of bacteria and infectious diseases is unclear. This study aimed to explore the interaction between a eukaryotic cell line HEK293T and mineralized Escherichia coli, using a model of gold biomineralization on E. coli biofilms (E. coli-Au). In our present model, bacterial activity was not disrupted and bacterial adhesion and invasion were enhanced. E. coli-Au invaded the cytoplasm and nuclei of HEK293T cells and damaged them via intracellular growth and multiplication. The present findings indicate that metal biomineralization in bacterial biofilms for leaching of heavy metal ions is hazardous to eukaryotic cells and even human health.

The combination of novel airlift magnetic separation loop system and an efficient biosorbent for the removal of Pb(II) from aqueous solution

An efficient biosorbent containing magnetic nanoparticles, walnut shell powder, foam, and alginate (AMWSF) was prepared and used in Pb(II) removal. The adsorption process was performed in an airlift magnetic separation loop system. Optimum adsorption conditions were tested at pH 3-7, biomass dose of 0.03-0.4 g, temperature of 15-35 °C, initial Pb(II) ion concentration of 50-400 mg·L^-1, and contact time of 10-480 min. The equilibrium adsorption capacity reached up to 69.45 mg·g^-1. The physicochemical properties of AMWSF were analyzed by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy. The experimental data were in agreement with the pseudo-second-order kinetic and Langmuir isotherm models. The influences of Cu(II), Cd(II), and Zn(II) on Pb(II) adsorption showed antagonistic effect strength in the order of Cu(II) > Cd(II) > Zn(II). AMWSF was reused seven times and separated rapidly by magnetic field. The results demonstrated the potential of AMWSF in practical applications involving Pb(II).

Absorption characteristics of compound heavy metals vanadium, chromium, and cadmium in water by emergent macrophytes and its combinations

The aim of the present study was to investigate three kinds of emergent macrophytes, i.e., Acorus calamus L., Phragmites communis Trin., and Alternanthera philoxeroides (Mart.) Griseb and their combination patterns on their removal efficiency of compound heavy metals (vanadium, chromium, and cadmium) from synthetic aqueous. The results showed that the optimal single-species for compound heavy metals removal was Acorus calamus L. and during experiment period, the average removal efficiency of V⁵⁺, Cr⁶⁺, and Cd²⁺ was 52.4, 46.8, and 90.0%, respectively. Combination C (the quality ratio of Acorus calamus L., Phragmites communis Trin., and Alternanthera philoxeroides (Mart.) Griseb is 2:1:1) had the highest removal efficiency on compound heavy metals among three groups and the average removal efficiency of V⁵⁺, Cr⁶⁺, and Cd²⁺ was 18.0, 70.0, and 95.1%, respectively. The highest efficiency of combination C on V⁵⁺ removal was lower than single Alternanthera philoxeroides (Mart.) Griseb group; this may be an existing antagonism in different plants. Heavy metals of V⁵⁺, Cr⁶⁺, and Cd²⁺ had an obviously positive effect on SOD, CAT, and POD of emergent macrophytes. From these results, we conclude that in a phytoremediation for the removal of compound heavy metals where V was dominated pollution in water, the use of Acorus calamus L. species rather than a mixture of several plants should be suggested. When heavy metal pollution was dominated by Cr and Cd, group C rather than a single plant species should be used.